(3) Each LNA has a corresponding LNA
SHF oscillator in the BITE assembly for this check.
control panel located in the LNA control/translator. This
When the TEST switch is in the ON position, the LNA
unit allows control of the ac power, normal or high heat,
NORMAL lamp will illuminate if the LNA is operating
and control of the paramp and FET stages during testing
(2) Test translator. The LNA control/trans-
of the LNA when it is in standby. The TEST switches
allow checking the operation of either the paramp or FET
lator unit contains two modules, a power supply and
passive components that make up the test translator.
c. LNA Control/Translator. The LNA control/-
translator performs several distinct functions. These are:
output of the power amplifier ranges from about 37 dBm
operational control of the LNA, testing of the off-line LNA,
to 61 dBm (5 watts to 1250 watts). One port of the triple
fault detection in the LNA, loop testing control of the
section directional coupler in the PA samples this power
terminal, and monitoring. The LNA control/translator
range and provides a maximum signal of 0 dBm, i 3.
used in the AN/TSC-86 contains two independent LNA
The sample signal is sent to the test translator. An
attenuator, AT1, located in the LNA control translator
TRANSLATOR controls, and an LNA control MONITOR.
unit, further reduces the SHF signal before application to
Each independent LNA control unit contains a POWER
the double balanced translator mixer module. A 725-
breaker for application of power to the antenna-mounted
MHz signal from a 725-MHz source module mixes with
LNA. Either LNA control panel may be removed from the
the SHF signal and the resulting downconverted signal
control unit drawer for maintenance without interrupting
passes through to a second variable attenuator.
operation of the on-line units. Although contained in one
Upconverted signals are suppressed in the mixer. The
assembly, the LNA switching and testing electronics can
converted signal is now in the receive band of the
be treated as separate equipments.
terminal. The resulting coupler in the receive path. This
(1) LNA and on-line controls.
coupler attenuates the signal another 20 dB. The 725-
controls between the LNA controls allow switching either
MHz source is a phase-locked oscillator-multiplier. A 5-
LNA on line and the other to standby. STBY LNA TEST
MHz signal taken from the upconverter 5 MHz OUT jack
provides a means of checking the operational status of
is used as a frequency control. The 725-MHz source
the standby LNA. The TEST OSC switch turns on an
spurious signal output is about 60 dB down.